Use of cell phones has increased to a great extent but even then You have often heard that a cell phone is not allowed to be used on airplanes. Definitely it is so because this fact has a myth behind it and that is that cell phone can cause a jetliner to crash because they can not only interfere with avionics systems, but they are also popularly used by terrorists as detonation devices for bombs. And it is also obvious that excluding cell phone use within the confines of an airplane while in flight could counter an attack much like 9/11, actually when the cell phone attached to the bomb rings, the bomb explodes, and the plane comes crashing back down to the earth and destruction is obvious at that time.
It is rightly said that keeping the smart phones and PDAs off of planes is a good thing in cancellation the possible threat of cell phone detonated bombs on airplanes. So it is better not to use cell phones or similar devices on airplane in order to prevent the possible danger. It is also good to not to take risk and try to switch off cell phones or smart phones before moving to airplane.
It would be quite strange to know that cell phones can cause airplane to crash even without setting off a bomb but the chances of this happening are microscopic but it is obvious that cell phones can cause trouble or danger that is why they are not allowed during the flight.
Using SAMs surface to air missiles and other reactionary weapons cell phones can also be used to arrange an attack on a flight by other comrades on the ground, It is also strange and you will be wander to hear about flight phones that help you to make a call and these calls are quite different band than cell phones or smart phones and it is also strange that these calls do not interfere with the system of plan. So its better to avoid cell phones so that the possible danger can be decreased to the level of safety. Cell phones are not bad but can be used for bad purposes.